Front. Syst. Neurosci., 19 November 2013 |

Magnetic tracking of eye position in freely behaving chickens

Jason S. Schwarz*, Devarajan Sridharan* and Eric I. Knudsen
  • Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA

Research on the visual system of non-primates, such as birds and rodents, is increasing. Evidence that neural responses can differ dramatically between head-immobilized and freely behaving animals underlines the importance of studying visual processing in ethologically relevant contexts. In order to systematically study visual responses in freely behaving animals, an unobtrusive system for monitoring eye-in-orbit position in real time is essential. We describe a novel system for monitoring eye position that utilizes a head-mounted magnetic displacement sensor coupled with an eye-implanted magnet. This system is small, lightweight, and offers high temporal and spatial resolution in real time. We use the system to demonstrate the stability of the eye and the stereotypy of eye position during two different behavioral tasks in chickens. This approach offers a viable alternative to search coil and optical eye tracking techniques for high resolution tracking of eye-in-orbit position in behaving animals.

Keywords: eye tracking, bird vision, oculomotor control, eye movements, behavior, saccade, fixation, peck

Citation: Schwarz JS, Sridharan D and Knudsen EI (2013) Magnetic tracking of eye position in freely behaving chickens. Front. Syst. Neurosci. 7:91. doi: 10.3389/fnsys.2013.00091

Received: 26 August 2013; Accepted: 29 October 2013;
Published online: 19 November 2013.

Edited by:

Detlef H. Heck, University of Tennessee Health Science Center, USA

Reviewed by:

Martijn Schonewille, Erasmus MC, Netherlands
Ziad M. Hafed, University of Tuebingen, Germany

Copyright © 2013 Schwarz, Sridharan and Knudsen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Jason S. Schwarz and Devarajan Sridharan, Department of Neurobiology, Stanford University School of Medicine, 299 Campus Drive West D200, Stanford, CA 94305, USA e-mail:;